|MINIER, DOUG - Michigan State University|
|NEHER, OLIVER - Amalgamated Sugar Company|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2022
Publication Date: 12/3/2022
Citation: Hanson, L.E., Minier, D.H., Neher, O.T. 2022. Colletotrichum coccodes causing "black dot" of sugar beet in the Pacific Northwest of the USA. Plant Disease. 46: Article e12135. https://doi.org/10.1002/ndr2.12135.
Interpretive Summary: An unusual root rot was found on sugar beet from Idaho and Washington in fall of 2014. The fungus Colletotrichum coccodes was isolated from these beets and caused similar symptoms on tested beets. The beets came from fields with a history of crops known to be susceptible to this pathogen. This appears to be a new disease for sugar beet in the United States.
Technical Abstract: An unusual shallow root rot was found on sugar beet samples from Idaho and Washington in fall of 2014. Samples from this tissue yielded a fungus that was subsequently identified as Colletotrichum coccodes. A similar shallow, firm rot was produced when mature beets were inoculated with this fungus. Another Colletotrichum species, C. dematium has previously been found on beets (sugar or table) in other countries, but to our knowledge this is the first report of a Colletotrichum species on sugar beet in the field in the United States and the first report of C. coccodes from sugar beet. The diseased beets were found in fields with a history of potato and onion production and C. coccodes is a common potato pathogen. Thus sugar beet may be serving as an alternate host for black dot of potato. It appears to be causing primarily cosmetic damage on sugar beet but investigations on the effects of the disease on storage are recommended.